Comedian Russell Brand has revealed he had a filmed sexual encounter with a man in a pub toilet while in the thralls of heroin.

Recounting the story in an podcast interview with fellow Brit comedian Richard Herring, Katy Perry's ex-hubby candidly admitted: "I w**ked off a man in a toilet."

The 38-year-old says the shocking scenario was all part of a TV stunt for a documentary he was working on.

He said: "I thought, 'I think of myself as heterosexual but perhaps that's 'cause of the environment that I grew up in where homosexuality may have been difficult for me to express.

He then went on, in incredibly fine detail, about his attempt to find a stranger to take part in the experiment.

"I trawled around Soho... going [to] various gay bars, gay gyms trying to pick people up with a film crew. I went in this pub and I goes: 'Anyone want me to w*** them off?'

"And this bloke goes, 'Yep'. Like as if I was saying: 'Does anyone want a packet of crisps from the bar...?'

"So we goes to the lavvy - me, him, the director - and... he gets his willy out. And it was not nice. The phallus is... I like mine and you see some others in paintings that look all right but his looked like a rag."

He then goes on to explain what it felt like: "I took it betwixt my fingers thusly. It were like massaging a naked mole rat and it wouldn't go hard!"

And then the director persuaded him to allow the man to perform a sex act on him.

He finished off the not-so-steamy sexual episode-sharing by saying he still wanted to do a good job - despite not enjoying it - because he's a "sexy narcissist."

The show, RE: Brand, which aired back in 2002, also saw the comedian have a bath with a homeless person and stay with a prostitute and her family.